Fuel burner apparatus



R. W. BROWN Filed Jan. 20, 1966 FUEL BURNER APPARATUS sept. 5, 1967 INVENTOR. RICHARD w. BRowN BY Z/ ATTORNEY United States Patent O 3,339,615 FUEL BURNER APPARATUS Richard W. Brown, Excelsior, Minn., assignor to Honeywell Inc., Minneapolis, Minn., a corporation of Delaware Filed Jan. 20, 1966, Ser. No. 521,928 Claims. (Cl. 158-28) ABSTRACT OF THE DISCLOSURE A fuel burner device that utilizes a step-up ignition transformer that is mounted in the air tube ofthe fuel burner and which substantially fills the central portion of the air tube to form an air diversion means to cause the air to flow around the transformer. The air fiow is diverted for proper combustion and also simultaneously cools the transformer by passing over the transformer and its laminations.

The present invention is directed to an improved type of fuel oil burner ignition transformer, and more particularly is directed to a fuel burner combustion device wherein the transformer is taken from its normal mounting location and is placed in the air tube of the burner at a location immediately adjacent the area where the fuel and combustion air are mixed for ignition.

In a conventional fuel burner, particularly of the gun type oil burner design, an ignition transformer which provides a high voltage ignition spark is conventionally mounted as an appendage to the mechanical burner equipment, such as the blower, motor, and pump. In this normal configuration it is necessary to conduct the transformer high voltage potential, in the range of 10,000 volts, from the transformer secondary to the ignition electrodes which are at a point near the end of the air tube within the furnace or fire chamber. This construction requires careful electrical and mechanical support of 10,- 000 volt conductors over a relatively long path,` and results in both direct manufacturing problems of mechanical and electrical nature, as well as operational and field service problems. In the operation of a burner of a conventional design careful electrical interference shielding must be provided and provisions must be made to regularely clean any lint or dirt accumulation away from the high voltage supports so that arcing and breakdown are avoided.

In the present invention, the ignition transformer of a conventional gun type of oil burner is completely redesigned to a configuration which can be mounted in the end of the oil burner air tube at the point where the air is diverted to the outer periphery of the air tube prior to mixing with the fuel for combustion. The mounting of the transformer at this particular location provides two major and distinct functions of a beneficial nature. The transformer and its mounting provide the necessary diversion means so that the air is directed to the outer periphery of the air tube prior to mixing with the fuel for combustion, and further this arrangement shortens the high voltage leads to the point where the ignition electrodes can be mounted directly on the transformer.

The placement of the ignition transformer at this particular location in the air tube provides a great number of benefits that are not possible with the more conventional mounting of an ignition transformer. More specifically the transformer can be made substantially smaller sincel the transformer is air cooled by the combustion air passing around the transformer. With this better heat ydissipation location, the transformer as well as being made smaller, has a longer life due' to a smaller temperature rise than would be normal if the trans- Patented Sept. 5, 1967 former did not have the benefit of air cooling. The placement of the transformer immediately adjacent the point where the fuel and air mixture is ignited, allows for very short high voltage leads. This eliminates the normal mounting problems of the high tension or high voltage leads down the air tube thereby making the installation substantially cheaper and more reliable. The placement of the high voltage section within the air tube, which is a grounded metal member, eliminates much of the radio interference problem by automatically shielding the transformer and ignition point in an efficient manner. Location of the transformer at the diversion point for the air provides the dual function of air cooling the transformer and providing for an air diversion means that otherwise would have to be placed in the air tube. This dual function of the mounting of the transformer and air diversion means simplifies the construction and reduces the cost and further provides a mounting location for auxiliary equipment for fiame safety, such as a flame sensing means.

The structure specifically disclosed and claimed, can be substituted in conventionally designed burners now marketed and is also available for newly designed gun type oil burners allowing for a smaller, more compact 4and pleasing in appearance type of unit. Due to the fact that this type of oil burning equipment is now more extensively used in areas where the physical appearance and size area factor, the additional benefit of locating the ignition transformer in the air tube lends itself to this compactness and to the saleability of this type of general device.

In connection with the disclosure of the present invention, the drawing discloses significant variations of the structure wherein:

FIGURE l is a schematic representation of a gun type oil burner utilizing an air tube with the transformer mounted therein;

FIGURE 2 is an end view of a radial transformer design;

FIGURE 3 is a cross-section of FIGURE 2 taken along lines 3 3; and

FIGURES 4 and 5 are an end View and cross-section, respectively, of a more conventional transformer structure incorporating the present invention.

In FIGURE 1 there is disclosed generally at 10 a gun type of fuel oil burner which includes a drive motor 11 connected by shaft 12 to a blower 13 which in turn is connected by shaft 14 to an oil pump 15. The oil pump 15 is fed by an oil line 16 and has an outlet pipe 17. The outlet pipe 17 connects to an oil valve 20 which can be of a type disclosed in the U.S. Patent 2,968,466 to Mc- Goldrick. The valve means 20 is connected by pipe 21 to an oil pipe or conduit 22 that terminates in a nozzle 23 where the supplied oil is mixed with air for combustion.

Also included in the gun type fuel oil burner system disclosed at 10 is a thermostat 25 that is connected to conductors 26 and 27 which are supplied from an electrical source generally shown at 28. The conductor 27 along with a conductor 30 supply power from the source 28 through the thermostat 25 to a safety control means 31. The safety control means 31 is a conventional primary safety control type for oil burners. The safety control means 31 supplies power via conductors 32 and 33 to the motor 11 and by conductors34 and 35 to the oil valve 20. The primary safety control means 31 also supplies electrical energy at a line voltage -on conductors 40 and 41 where they pass into an air tube 42 of the gun ty-pe of oil burner 10. The air tube 42 is a conventional round tube that will be described in some detail in connection with FIGURES 2 through 5. The air tube 42 passes through a refractory wall 43 that forms the wall of a device such as a furnace or water heater. Also passing into the air tube 42 are a pair of conductors 45 and 46 which lead to a flame detector 47 that operates in conjunction with the primary safety control means 31 to control the potential on conductors 40 and 41 to a stepup transformer means 50 that forms part of the present invention. The step-up transformer means 50 and its associated equipment will be described in detail in connection with FIGURES 2 through 5 and is merely recited in general terms in the description of FIGURE l to orient the location and operation of the parts of the device. The transformer means 50 has a pair of electrodes 51 to which the high voltage side of the transformer means 50` is connected to provide an ignition arc adjacent the nozzle 23 for ignition of oil supplied in the conduit 22, in a conventional fashion in the operation of a gun type of fuel oil hurner.

In operation, the system disclosed in FIGURE 1 is substantially as follows. Power is supplied through the thermostat 25 which in turn supplies power to the primary safety control means 31. When power is supplied to the primary sa-fety control means 31, the motor 11 is energized thereby operating the blower 13 and the pump 15. Oil is supplied through the valve means 20 to the nozzle 23 as air flows in the air tube 42. At this same time power is supplied by conductors 40 and 41 to the transformer means 50 and a high voltage ignition spark is generated between electrodes 51. The air iowing in the air tube 42 passes over and around the transformer means 50, and is forced to the outer edge of the air tube 42 by the restriction that the transformer means 50 forms. This air then iiows in the air tube -42 and mixes with the fuel from nozzle 23 where the fuel is ignited. As soon as the fuel is ignited, the ame sensor 47 supplies a signal on conductors 45 and 46 back to the primary safety control means 31 which removes the potential from conductors 40 and 41 thereby turning oif the spark across the electrodes 51. The system then operates as a normal oil burner.

The novelty of the present invention is in the design and location of the transformer means 50. The transformer means 50 is located in the air tube 42 at a point adjacent to the electrodes 51 and the nozzle 23. 'Iwo specific constructions of transformers for this invention are disclosed in FIGURES 2-5. In FGURES 2 and 3, a toroidal or annular type of transformer structure is shown. in FIGURES 2 and 3, the blast tube 42 is shown in crosssection with a plurality of transformer coils 60, 61 and 62 all mounted coaxially on a core 63. The core 63 in turn supports a plurality of laminations 64 that project radially outward from the core 63. The core 63 also has a passage or conduit 65 that passes through its center to the nozzle 23 of the present device. The passage 65 is connected to the conduit 22 for receipt of fuel oil to the nozzle 23. The oil passing through the core 63 performs a cooling action in operation.

The coil 60 of the transformer means 50 is connected to the conductors 40 and 41 as corresponds to FIGURE 1. The coils 61 and 62 have mounted lon a flange 66 a pair of insulating projections 67 into which are mounted the electrodes 51. The electrodes 51 are internally connected through the flange 66 to the ends of the step-up or secondary coils 61 and 62. The mounting of the electrodes 51 in the insulating mounts 67 can best be seen in FIG- URE 2.

The device described to this point in FIGURES 2 and 3 is shown as insulated by air between the coils 60, 61, 62, the laminated structure 64 and core 63. In a practical embodiment, this arrangement would be potted in an insulating material. This has not been shown on the drawings for claritys sake but would normally be incorporated thereby making the center of the transformer means 50 a solid mass to the outer edge 7 0 of the transformer means 50. In FIGURE 2 the outer edge 70 is shown as separated from the inner surface 71 of the air tube 4Z. It is thus apparent that a plurality of air spaces 72 are provided between the edge 70 of the transformer coils and the inner surface 71 of the air tube 42. As air Hows in the air tube 42 and comes to the transformer means 50, the air is diverted through the plurality of air spaces 72 thereby passing along the sides of the laminations 64. This provides two separate and distinct functions that form the present invention. The air flow in the spaces 72 provides a cooling of the laminations 64, thereby cooling the transformer generally, and also provides the diversion of the air ow in the air tube 42 to the outer surface 71 where it passes to a chamber generally indicated at 73. The air in chamber 73 mixes withthe oil from the nozzle 23 in a combustible manner which is ignited by the electrodes 51 in the inauguration of the flame for the oil burner. Once a flame has been inaugurated in the chamber 73, it is directed by walls 74 to the furnace in a conventional manner through an `opening 75. No further description of this structure is believed necessary as it is the conventional structure of the end of an air tube of a gun type of oil burner. It is also noted that the sensor 47 is exposed to chamber 73. As soon as a flame is established in the chamber 73, the sensor 47 provides a -signal on conductors 45 and y46 to the primary safety control means 31 thereby turning off the power yon conductors 40 and 41 to the transformer means 50. It will be noted that the laminations 64, particularly at 46 and 46" mount the sensor 47 in the air stream supplied in the air tube 42. With this structure the sens-or 47 is also air cooled by the combustion air prior to the time it reaches the chamber 73 where it is mixed for combustion.

In FIGURES 4 and 5, a more conventional transformer is disclosed incorporating the present invention. Transformer means 50 is supplied in a conventional form having end bells and 81 attached to a. conventional lamination stack 82. This transformer `structure is of the type in which at laminations are stacked to form a magnetic circuit for the electrical windings. Conductors 40 and 41 again are supplied through the end bell 81 to the primary (not shown) which in turn is coupled to the secondary (not shown) and the secondary is connected to electrodes 51 which are mounted in a pair of ceramic insulators 83 and 84. The ceramic insulators 83 and 84 provide a convenient mounting for the electrodes 51 and also help mount the transformer means 50 to a plate 85. The plate 85 mounts the transformer means 50 `and the block 89 to which the conduit 22 is connected that in turn supplies the oil to the nozzle 23. The conduit 22 is -connected to nozzle 23 by a passage (not shown) within the block 89 so that oil flow can proceed through the conduit 22 to the nozzle 23 for combustion in the chamber 73.

The plate 85, as can be seen in FIGURE 4, has four projects 86 which support the plate 85 in the middle of the air tube 42 leaving an air space 72' between the edge 87 of the mounting plate 85 and the inside surface 71 of the air tube 42. It is thus seen that a large air space 72 is provided around the edge 87 of the mounting plate 85 so that the air flow in the air tube 42 proceeds until it reaches the transformer means 50 and then is directed around the outer surface of the transformer 50 through the space 72'. This structure provides convenient mounting of the transformer means 50 in the air tube 42 and also provides for the air cooling of the transformer 50 by passing air over the end bells 80 and 81 and the laminations 82. It is noted that the oil conduit 22 passes alongside of the plate 85 in the air space 72 and it is not necessary that a hole be provided through the laminated structure 82 for this member. Also attached to the plate 85 is a projection 90 which supports the flame detector 47 in an air space 72 so that the detector 47 is air cooled during the operation of the device. If it is found desirable, additional projections 91 can be provided between the inside wall surface 71 of the air tube 42 and the end bells 80 and 81 of the transformer means 50 to rigidly support the transformer. The projections 91, as well as the plate 85 can be attached to the transformer means 50 by any convenient technique, such as welding, or can be integrally formed during the manufacture of the transformer means 50. The particular configuration of the mounting means 85 and of the projections 91 are not material other than that they properly support the transformer means 50 in the air tube 42 so as to place it adjacent the chamber 73 and provide for an air passage 72 around the transformer means 50.

In considering the invention disclosed in FIGURES 2-5 it is noted that either a specially formed radial transformer or a conventional type transformer can be used. It is further obvious that the two prime benefits of the invention are available with either structure. These two prime benefits are the air cooling (along with the allowable reduction in size and cost of the transformer) and the exceedingly short high voltage leads to the electrodes 51. This structure, due to its placement and configuration in each case, provides the necessary combustion air diverter means so as to force the combustion air to the outer edge of the air tube 42 so that the air can properly be forced into the chamber 73 for combustion. It is obvious that many modifications are possible of the present invention and the applicant therefore wishes to be limited only by the scope of the appended claims.

I claim as my invention:

1. In a fuel burner including an air tube into which a combustion air source is directed, a source of fuel under pressure connected to conduit means carried within the air tube, air diversion means near an outlet end of the air tube to direct the combustion air into a relationship with fuel carried by the fuel conduit means for proper combustion of the fuel, electrode means for ignition of the air and fuel mixture at the outlet end of the air tube, the improvement comprising: said air diversion means including voltage step-up transformer means to supply an ignition potential to said electrode means; and said transformer means forming a center portion of said air diversion means and substantially filling the center portion of said air tube to provide said air diversion means with a generally annular air flow passage adjacent said air tube; said transformer means being cooled by said combustion air passing over said transformer means in progressing through said annular air fiow passage prior to said air mixing with said fuel for combustion.

2. A fuel burner as described in claim 1, wherein said conduit means passes through the transformer means t0 cause the fuel ow to additionally cool said transformer means.

3. A fuel burner as described in claim 1, wherein said diversion means supports fiame detection means so said flame detection means is cooled by said combustion air iiow.

4. In a fuel burner including an air tube into which a combustion air source is directed, a source of fuel under pressure connected to -conduit means carried Within the air tube, air diversion means near an outlet end of the air tube to direct the combustion air into a relationship with fuel carried by the fuel conduit means for proper combustion of the fuel, electrode means for ignition of the air and fuel mixture at the outlet end of the air tube, the improvement comprising: said air diversion means including voltage step-up transformer means to supply an ignition potential to said electrode means; said transformer means being cooled by said combustion air passing over said transformer means in progressing through said diversion means prior to said air mixing with said fuel for combustion; said voltage step-up transformer means including radial lamination means having air spaces at the outer periphery of said transformer means to form said diversion means and provide a large lamination area exposed to said air flow to allow the air flow to cool said transformer means.

5. A fuel burner as described in claim 4 wherein said conduit means passes through said lamination means to cause the fuel fiow to additionally cool said transformer means.

References Cited UNITED STATES PATENTS 1,762,555 6/1930 Kiefer 158-28 1,897,310 2/1933 Kiefer 158-28 FOREIGN PATENTS 1,089,223 9/ 1954 France.

JAMES W. WESTHAVER, Primary Examiner. 

1. IN A FUEL BURNER INCLUDING AN AIR TUBE INTO WHICH A COMBUSTION AIR SOURCE IS DIRECTED, A SOURCE OF FUEL UNDER PRESSURE CONNECTED TO CONDUIT MEANS CARRIED WITHIN THE AIR TUBE, AIR DIVERSION MEANS NEAR AN OUTLET END OF THE AIR TUBE TO DIRECT THE COMBUSTION AIR INTO A RELATIONSHIP WITH FUEL CARRIED BY THE FUEL CONDUIT MEANS FOR PROPER COMBUSTION OF THE FUEL, ELECTRODE MEANS FOR IGNITION OF THE AIR AND FUEL MIXTURE AT THE OUTLET END OF THE AIR TUBE, THE IMPROVEMENT COMPRISING: SAID AIR DIVERSION MEANS INCLUDING VOLTAGE STEP-UP TRANSFORMER MEANS TO SUPPLY AN IGNITION POTENTIAL TO SAID ELECTRODE MEANS; AND SAID TRANSFORMER MEANS FORMING A CENTER PORTION OF SAID AIR DIVERSION MEANS AND SUBSTANTIALLY FILLING THE CENTER PORTION OF SAID AIR TUBE TO PROVIDE SAID AIR DIVERSION MEANS WITH A GENERALLY ANNULAR AIR FLOW PASSAGE ADJACENT SAID AIR TUBE; SAID TRANSFORMER MEANS BEING COOLED BY SAID COMBUSTION AIR PASSING OVER SAID TRANSFORMER MEANS IN PROGRESSING THROUGH SAID ANNULAR AIR FLOW PASSAGE PRIOR TO SAID AIR MIXING WITH SAID FUEL FOR COMBUTION. 